dggccbug.c

/* NOCW *//* dggccbug.c *//* bug found by Eric Young (eay@cryptsoft.com) - May 1995 */#include <stdio.h>/* There is a bug in * gcc version 2.5.8 (88open OCS/BCS, DG-2.5.8.3, Oct 14 1994) * as shipped with DGUX 5.4R3.10 that can be bypassed by defining * DG_GCC_BUG in my code. * The bug manifests itself by the vaule of a pointer that is * used only by reference, not having it's value change when it is used * to check for exiting the loop. Probably caused by there being 2 * copies of the valiable, one in a register and one being an address * that is passed. *//* compare the out put from * gcc dggccbug.c; ./a.out * and * gcc -O dggccbug.c; ./a.out * compile with -DFIXBUG to remove the bug when optimising. */void inc(a)
int *a;
{
(*a)++;
}
main()
{
int p=0;
#ifdef FIXBUGint dummy;
#endifwhile (p<3)
{
fprintf(stderr,"%08X\n",p);
inc(&p);
#ifdef FIXBUG dummy+=p;
#endif }
}